Muh. Nur Khoiru Wihadi, Fasih Bintang Ilhami, Akhmad Syafi’i Ma’arif
We investigated the adsorption behavior of tetrachloro-aurate(III) (AuCl4−) under a single solution and in the presence of dichromate(VI) (Cr2O72−) ion on Mg/Al LDH. The most effective adsorption of AuCl4− ion occurred at a pH of 3; the optimum time was 600 minutes. The kinetics studies demonstrated that the adsorption of AuCl4− ion on Mg/Al LDH adhered to a pseudo-second-order kinetic model. The rate constant (k) was 2.877 x 10−3 and 13.696 x 10−3 g. mg−1. min−1 for the single and binary conditions, respectively. The isotherm model was evaluated by employing many models, including Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Flory-Huggins, Fowler-Guggenheim, Hill-de Boer, Jovanovic, Harkins-Jura, and Halsey. The R2 analysis indicates that the isotherm accurately fits the adsorption data of AuCl4− onto Mg/Al LDH. The X-ray diffraction (XRD) patterns of the Mg/Al LDH exhibit noticeable variations in the d003, d006, d009, and d009. A slight shift towards higher 2θ values was observed in the peaks, resulting in a minimal reduction in the interlayer spacing. The IR spectra detected a specific absorption peak at 3456.44, 1381.03, 678.94, 447.48, and 563.21 cm1−. These peaks correspond to the stretching vibrations of the O-H, O-N-O, N=O, Mg-O, and Al-O bonds in the Mg/Al LDH. The initial specific surface area of Mg/Al LDH was 20.49 m2 g−1. However, after AuCl4− adsorption in both conditions, the surface area reduced to 13.81 and 3.74 m2 g−1. The Mg/Al LDH had a coarse and irregular shape, with the adsorbent surface predominantly composed of smaller particles. In conclusion, the presence of dichromate(VI) species reduced tetrachloro-aurate(Ш) adsorption capacity on Mg/Al LDH. © 2025, University of Mohammed Premier Oujda Morocco.
Research Center for Chemistry, National Research and Innovation Agency (BRIN), Republik Indonesia, Kawasan Sains dan Teknologi (KST) B. J. Habibie, Tangerang Selatan, 15311, Indonesia; Department of Natural Science, Faculty of Mathematics and Natural Science, Universitas Negeri Surabaya, Surabaya, 60231, Indonesia; Metal Oxide Research Group, HAMNOX Institute, Warungasem, Batang, 51252, Indonesia
